diff -ru tcsh-6.17.00-orig/sh.c tcsh-6.17.00/sh.c
--- tcsh-6.17.00-orig/sh.c	2009-06-25 23:15:37.000000000 +0200
+++ tcsh-6.17.00/sh.c	2009-09-10 15:38:50.703642142 +0200
@@ -336,12 +336,14 @@
     fix_strcoll_bug();
 # endif /* STRCOLLBUG */
 
-    {
+    if (MB_CUR_MAX == 1) {
 	int     k;
 
-	for (k = 0200; k <= 0377 && !Isprint(CTL_ESC(k)); k++)
+	for (k = 0200; k <= 0377 && !isprint(CTL_ESC(k)); k++)
 	    continue;
-	AsciiOnly = MB_CUR_MAX == 1 && k > 0377;
+	AsciiOnly = k > 0377;
+    } else {
+	AsciiOnly = 0;
     }
 #else
     AsciiOnly = getenv("LANG") == NULL && getenv("LC_CTYPE") == NULL;